Lorentz Transformations

Length Contraction (or Lorentz Contraction)

Suppose that a ruler of rest
length is moving with constant
speed v in the direction of its own length with respect
to an observer. The observer, however, will observe the
length to be

This formula is the so-called length contraction formula. Note
that for all speeds , which means that
the ruler is contracted according to the observer. Moving
rulers are shorter! Note also, that the spatial dimensions
perpendicular to the direction of motion, are not affected
by the length contraction.